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in direction. A deflection in the wind, in the opposite direction to what is now described, sometimes takes place, but not so frequently. As to whether these deviations are in regular curves, and are segments of large circles, or merely deflections in the course of the currents caused by some peculiarity in the situation of the places, or whether it be our insular position that modifies the currents, I cannot venture an opinion. The course of the currents is, as might have been expected, much more steady at Plymouth than at Birmingham. Thus on the 29th, 30th, and 31st of January last, the wind commenced at due west, and veered at a perfectly even rate round to the north: while in Birmingham the course of the current was exceedingly unsteady, and veered round one half the compass, in Plymouth it only moved one quarter. This, among many other instances which I could bring forward, shows that great care should be taken in the selection of stations for making observations concerning the course of the main currents of the atmosphere, which ought to be our principal object in the first instance; for we must not hope, for a long time to come, to lay down the minor fluctuations by which the greater ones are modified.

I shall conclude with a few remarks on the great storm of the 6th and 7th of January last (1839), that committed such dreadful ravages in this country, and trace its probable course and action. In addition to the records obtained by the anemometer at this place and at Plymouth, I have collected what information I could concerning the nature and extent of this storm from many parts of the British Isles. A careful analysis of these strongly leads me to the opinion that this was a small but violent rotatory storm, moving forward at the rate of about thirty to thirty-five miles per hour. The diameter of the rotating portion I am not prepared to give, nor do I consider it at all certain that it could be ascertained, as it seems likely that the revolutions were not in contact with the earth. The tendency of this eddy, or violent whirling of the air, would, of course, be to produce a vacuum in the centre. The air that forms the eddy being constantly thrown off in a slight degree spirally upwards, and dispersed in the upper portion of the atmosphere, the effect of this would be to produce a strong current upwards. Now, supposing this large eddy to be perfectly stationary, there would be a rapid rush of air towards it from all sides, which would be drawn up and thrown off through this rotating circle, and dispersed with amazing rapidity above: but as it is moving on with great velocity, the air that is in the advance of the storm is not sensibly affected until the whirl is close to it; while in the rear the motion of the air is greatly increased first, by the tendency of the air to rush into the great vortex of the storm; and, secondly, by the motion onward of the vortex itself. This vortex or revolving column would increase in size upwards, so as somewhat to resemble a funnel; it would in fact be similar in its shape and action to an immense water-spout; whether it was vertical or not is entirely a matter of conjecture, but I should consider it probable that it would incline in the direction that the storm was moving; namely, to the N.E., and that it was an upper current that carried it in that direction. The greatest intensity of the storm in England was evidently across

Lancashire and Yorkshire. I therefore conceive that the nucleus of the hurricane passed in a N.E. direction over these two counties. Towards the sides, however, a little current set in a S. and even slightly in a S.E. direction, on the S. side of the vortex, and in a N.W. and westerly direction on the N. side, as before stated; but the main rush was behind. The anemometer at Birmingham shows that we here first felt a fresh S. wind with a slight bearing of E. in it, which very shortly became more westerly, increasing considerably in violence, and it then moved round to the S.W., and became quite a hurricane, and continued so, very violent at first, but decreasing in strength during the remainder of the day at Plymouth it commenced as a S.W. and then very gradually moved round a little more westward. It was by careful examination of the records of these two instruments that I arrived at the view I ventured to take of this storm; and the evidence that I have collected from various parts of the country concerning it, strongly confirms me in the opinion I have taken of it. Many violent storms followed in the wake of this extraordinary hurricane, but I have not attempted to investigate these, as the main storm must have thrown the atmosphere into so disturbed a state, that it would be very likely to produce minor eddies, gusts, &c.

On the Temperature of the Earth in the deep Mines of Lancashire and Cheshire. By Mr. EATON HODGKINSON.

These experiments were made with thermometers belonging to the Association, and in the prosecution of them the author has been very greatly assisted by the proprietors of pits and others connected with them, who have kindly undertaken to observe the results themselves— thus saving the author the trouble, in some cases, of going more than once into the mine. In the salt mines of Messrs. Worthington and Firth, at Northwich, in Cheshire, latitude about 53° 15', a thermometer placed in a bore-hole 3 feet deep in the rock, 112 yards below the surface, indicated a temperature of 51° to 514° Fahr., and varied little or nothing between summer and winter. In the deep coal-mines of Messrs. Leeses, Jones, and Booth, near Oldham, a thermometer, placed in a bore-hole as before, 3294 yards below the surface, varied from 57° to 581° Fahr., from observations made for a whole year by Mr. J. Swain. In the Haydock colliery, 201 yards deep, about 18 miles west of Manchester, and differing from it but little in latitude, the temperature varied considerably, both in the same hole and in different ones, but approached to 58°. The cause of these anomalies the author has not discovered. The experiments were made for him by Mr. William Fort. Other experiments are in progress. The latitude of Manchester is 53° 30', and the mean temperature of the air there is 48° Fahr., from Dr. Dalton's experiments.

On a New Calorimeter, by which the heat disengaged in combustion may be exactly measured, with some introductory Remarks upon the Nature of different Coals. By ANDREW URE, M.D.

After some remarks on the quantity of sulphur in coal, and a table of results obtained by analysis, Dr. Ure thus describes his Calorimeter and its application. The apparatus which I employ consists of a large copper bath capable of holding 100 gallons of water: it is traversed, forwards and backwards, four times, in four different levels, by a zigzag horizontal flue, or flat pipe, nine inches broad, and one inch deep, ending below in a round pipe, which passes through the bottom of the copper bath, and receives there into it the top of a small black lead furnace. The interior furnace, which contains the fuel, is surrounded, at the distance of an inch, by another furnace, which case serves to prevent the dissipation of heat into the atmosphere. A pipe, from a pair of double-cylinder bellows, enters the ash-pit of the furnace at one side, and supplies a steady current of air to keep up the combustion, kindled at first by half an ounce of red-hot charcoal. So completely is the heat which is disengaged by the burning fuel absorbed by the water in the bath, that the air discharged at the top orifice has usually the same temperature as the atmosphere. In the experiments made with former water calorimeters, the combustion was maintained by the current of a chimney, open at bottom, which carried off at top a quantity of heat very difficult to estimate. My experiments have been directed hitherto chiefly to a comparison of the heating powers of Welsh anthracite, Llangennech, and a few other coals. I have found, that the anthracite, when burned in a peculiar way, with a certain small admixture of other coals, evolves a quantity of heat at least 35 per cent. greater than the Llangennech does, which latter is reckoned by many to be the best fuel for the purposes of steam navigation. One half-pound of anthracite, burned with my apparatus, heats 600 pounds of water 10° Fahr., viz. from 62° to 72°, the temperature of the atmosphere being 66°; whereby no fallacy is occasioned either by the conducting powers of the surrounding medium, or by a chimney current. We thus see that one pound of anthracite will communicate, to at least 12,000 times its weight of water, an elevation of temperature of 1o, by Fahrenheit's scale. For the sake of brevity, we may call this quantity, or energy, 12,000 unities of heat. One pound of Llangennech, in the same circumstances, will afford 9,000 unities: one pound of good charcoal, after ordinary exposure to the air, affords 10,500: perfectly anhydrous charcoal would yield much more: one pound of Lambton's Wall's-end coals affords 7,500 unities. It deserves to be remarked, that a coal, which produces in its ignition much carburetted hydrogen and water, does not afford so much heat as a coal equally rich in carbon, but of a less hydrogenated nature, because, towards the production of the carburetted hydrogen and water a great deal of latent or specific heat is required: indeed, the evaporation of unburnt volatile matter from ordinary flaming coals abstracts unprofitably a very large portion

of their heat, which they would otherwise afford. Hence, those chemists who, with M. Berthier and Mr. Richardson, estimate the calorific powers of coals by the quantity of carbon which they contain, or the quantity of oxygen which they consume, have arrived at very erroneous conclusions. The amount of error may be detected by experiments on the cokes of flaming coals. M. Berthier examines coals for their proportion of carbon, by igniting a mixture of each, finely pulverized, with litharge, in a crucible, and estimates 1 part of carbon for every 34 parts of lead which is reduced. I have made many researches in this way with both charcoal and anthracite, and have obtained very discordant results. In one experiment, 10 grains of pulverized anthracite, from the vale of Swansea, mixed with 500 grains of pure litharge, afforded 380 grains of metallic lead; in a second similar experiment, 10 grains of the very same anthracite afforded 450 grains of lead; in a third, 350 grains. In one experiment with good ordinary charcoal, fresh calcined, 10 grains, mixed with 1,000 of litharge, afforded no less than 603 grains of metal. The crucible was in each case covered and luted. My future researches, which are intended to embrace every important variety of fuel, natural and artificial, will be made with an apparatus somewhat modified from that here described. Three furnaces will be inclosed within each other, with a stratum of air or ground charcoal between each, so as to prevent all loss of heat into the atmosphere, and thereby to transfer the whole heat disengaged by combustion into a large body of water, of a temperature so much below that of the atmosphere at the beginning of the experiment, as it shall be above it at the conclusion.

On a method of filling a Barometer without the aid of an Air-pump, and of obtaining an invariable level of the surface of the Mercury in the Cistern. By Prof. STEVELly.

Prof. Stevelly said that it was very difficult to fill a barometer tube so as to be quite free from air and moisture. Mr. Daniell, in his Meteorological Essays, proposed to fill the barometer under the exhausted receiver of the air-pump, and actually had the barometer of the Royal Society so filled by Mr. Newman, under his own superintendence; but, although an expert London working optician might be found capable of executing successfully such a task, yet few in the country could hope for such an advantage; and, in fact, although he had attempted the process at Belfast, he had never succeeded. After some consideration, the following simple mode of using the Torricellian vacuum of the tube itself, instead of the air-pump, in filling it, occurred to him. He heated the mercury as hot as it could be handled, and filled the tube, in the common way, to within half an inch of the top; then worked out, in the usual way, all air-bubbles, as perfectly as possible; filled up the tube to the top, and inverted it in a cup of hot mercury, when of course it subsided, in the upper part of the tube, to the barometric height; he then placed his finger on the mouth of the tube, under the mercury in the

cup, and lifted it out; and, still holding his finger tightly over the mouth of the tube, laid it flat on a table, when the mercury in the tube soon lay at the under side of the tube, leaving the upper part along the length of the tube void. Upon then turning the tube slowly round, still keeping the finger on its mouth, every speck of air was gathered up. He then placed the tube in an upright position, with its mouth upwards, still keeping the finger firmly on; and, placing a funnel of clean dry paper about the upper part, an assistant filled the funnel with hot mercury, so as to cover the finger. Upon slowly withdrawing the finger, the mercury went gently in, and displaced almost perfectly the atmospheric air which had gathered into the void space. By renewing the process which succeeded the previous washing of the air out of the tube, once, or at most twice, a column of the most perfect brilliancy was obtained. He had mentioned this simple method to Dr. Robinson, of Armagh, who suggested that, to get rid of the damp and greasiness of the finger, it would be better to cover it during the process with clean and dry caoutchouc; and this was found a decided advantage.

The method of procuring an invariable surface in the cistern was equally simple. From the imperfection of the author's sight, it was an object of much interest to him to have as few readings or adjustments depending on sight as possible. He proposed, therefore, to divide the cistern into two compartments, by a diaphragm of sheet iron or glass, brought to a sharp edge at top. Into one of these compartments the barometer tube dips; in the other is placed a plunger of glass or cast iron, which can be raised or lowered by a slow screw movement. To prepare for an observation, the plunger is first screwed down, by which it displaces the mercury in one compartment, and raises its surface in the other above the edge of the diaphragm; upon raising it slowly again, the mercury drains off to the level of the edge of the diaphragm, thus, at every observation, reducing the surface to a fixed level.

A letter was received from Prof. A. D. Bache of Philadelphia, on the subject of rain at different heights. It is expected that this and other subjects will be treated of in the Report on the Meteorology of the United States of America, which Mr. Bache has undertaken to draw up for the Association.

Experiments to determine the Fluency or Viscidity of different Liquids at the same Temperature, and of the same Liquids at different Temperatures. By Dr. URE.

The author, referring to a memoir read to the Society of Civil Engineers, states a new mode of experiment and gives the results as under. Upon this occasion I put the liquid, either cold or heated to a certain temperature, into a glass funnel, terminated at its beak with a glass tube of uniform bore, about one eighth of an inch in diameter, and three inches long. The funnel was supported in a chemical stand, and dis

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